1. Field of the Invention
The present invention relates to an actuator/coupler device. In particular, to a device attached to a towed vehicle for releasably coupling the towed vehicle to a towing vehicle, and for actuating brakes on the towed vehicle.
2. Background
Devices for coupling towing and towed vehicles are well known in the art. These devices are necessary in order to assist the towing vehicle in braking situations. When the towing vehicle slows the towed vehicle tends to push or override the towing vehicle, thereby directing the momentum of the towed vehicle onto the towing vehicle during repeated stopping, which results in premature wear on the brakes of the towing vehicle. In addition, to increasing the wear on the towing vehicle brakes this effect can also make the towing vehicle difficult to control. In extreme situations this can lead to a jack-knife condition, or loss of control of the vehicles. Accordingly, a number of devices have been used over the years to not only couple a towed and towing vehicle, but also to assist in braking the towed vehicle in coordination with the towing vehicle under actual driving conditions.
These devices were originally quite simple and of limited effectiveness, especially for larger more modern towed and towing vehicle combinations. In recent times, the growth of the use of towed vehicles along with the increase in the size of such vehicles has required the development of more sophisticated devices. In particular, in order to ease the strain on the brakes of the towing vehicle and to provide strong braking in emergency situations, like in a break away situation, towed vehicles utilize independent brake systems actuated in response to changes in the speed of the towing vehicle.
The prior art discloses a number of methods for providing such capability. These include the use of electrical sensors to sense when the towed vehicle pushes against the towing vehicle, however, these systems proved troublesome in actual practice. Other systems utilize devices designed to sense changes in momentum between the towed and towing vehicles and apply towed vehicle brakes in response thereto.
One such device is disclosed in U.S. Pat. No. 5,013,059. The device includes a housing and a telescopically attached coupler. The coupler includes a brake actuator and shock absorber combination that is activated in response to compression of the housing and coupler caused by slowing of the towing vehicle. The device includes front and rear roller shafts, which extend through holes and slots in the coupler and housing, and which support a front and rear pair of juxtaposed rollers to facilitate low friction movement of the coupler and housing relative to each other. Because of the specific arrangement of the components the device requires that the front rollers extend through slots in the coupler to engage the inner surface of the housing. For this and other reasons, the device suffers from a number of practical operational drawbacks.
Thus, a need exists for an improved and simplified actuator/coupler device designed for attachment to the towed vehicle and for releasably coupling the towed vehicle to the towing vehicle, and for actuating brakes on the towed vehicle.